Method of producing uranium tetrachloride



Feb. 21, 1956 H R, MCCOMBlE ETAL 2,735,746

METHOD OF PRODUCING URANIUM TETRACHLORIDE Filed Feb. 23, 1944 4 Sheets-Sheet 1 N1 QM,

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Feb. 2l, 1956 HOD OF' PRODUCING URANIUM TETRACHLORIDE MET Filed Feb. 23, 1944 Feb. 21, 1956 H R, MCCOMBlE ET AL 2,735,746

METHOD OF PRODUCING URANIUM TETRACHLORIDE Filed Feb. 23, 1944 4 Sheets-Sheet 5 ATTORNEY.

Feb. 21, 1956 H, R, MCCQMB|E ETAL 2,735,746

METHOD OF' PRODUCING URANIUM TETRACHLORIDE Filed Feb. 23, 1944 '4 Sheets-Sheet 4 METHOD F PRODUCING URANIUM TETRACHLORIDE Horace R. McCombie, Pittsburg, Calif., and Edward L. Wagner, ak Ridge, Tenn., assignors, by mesne assignments, to the United States of America as represented by the United States Atomic Energy Commission Application February 23, 1944, Serial No. 523,602 Claims. (Cl. 23-14.5)

The invention relates to a Vprocess of and apparatus for making uranium tetrachloride. The invention is particularly concerned with a method of and apparatus for producing uranium tetrachloride in substantial quantities and of relatively high purity for use in technological processes and to produce technological products, and is more especially concerned with a means and a method of producing uranium tetrachloride from readily available materials in apparatus, and by techniques, that are readily producible and are easily and economically carried out.

It is an object ofthe invention to provide in general a satisfactory method of producing `uranium tetrachloride.

lt is another object of the invention to provide in general a mechanism or, apparatus for producing uranium tetrachloride.

dl Statt-#S Pacht@ n 2,735,746 Pisufed Feb- 21 1.9.5.6

In its preferred form, the apparatus for producing uranium tetrachloride, according to the invention, includes an inclined, rotatable, cylindrical chamber, into the lower end of which there is introduced a regulated supply of gaseous carbon tetrachloride, and from which end solid reaction products, including uranium tetrachloride, are released. The chamber is subjected to heat and is rotated in order to agitateits contents and to promote a chemical reaction between the carbon tetrachloride gas and solid, finely-divided uranium dioxide which is introduced into the upper end of the cylinder. From the upper'end gaseous reaction products are released to a condenser, which condenses unreacted carbon tetrachloride gas for re-use in the system and which discharges other gaseous reaction products. The supply of carbon tetrachloride and of uranium dioxide is substantially continuous and the removal of the solid reaction product,

which is approximately pure uranium tetrachloride, is

A further object of the invention is in general to improve methods ofV and apparatuses for producing uranium tetrachloride.

An additional object of the invention is to provide a continuous process of making uranium tetrachloride.

..An additional object of thekinvention is to provide mechanism which can be operated continuously for the production of uranium tetrachloride..

Other objects will appear from the vfollowing description of the invention and the preferred method of practicing it. One at present preferred embodiment of the apparatus is illustrated in the accompanying drawings, in which: Y

Figure l is in Vpart a diagrammatic representation and in part a side elevation Vof apparatus according to the iuvention, portions of the figurey being broken away to disclose internal construction and to reduce the size otthe figure, and portions of the ligure being in cross section on the longitudinal central vertical plane.

Figure 2 is a detail to an enlarged scale of a portion of the mechanism shown at the left end of Figure l, parts being broken away to reduce the size of the figure and to disclose internal construction, they planes of section being, in general, vertical and horizontal axial planes.

Figure 3 is a crosssection, the plane of which is indicated by the line 3-3 of Figure 2, parts of the structure being omitted for increased clarity of disclosure. Figure 4 is a View similar to Figure 2, but showing tol an enlarged scale the detailed construction of the mechamism illustrated in the right end of Figure l, portions seing in cross section the planes of which are generally iorizontal and vertical.

Figure 5 is a crosssection, the plane ,of whichV is inlicated by the line 5-5 of Figure l4, parts of the mecha- :ism being omitted for improved clarity. Y

Figure 6,is a cross'section, the plane of which is iniicated by the line 6-6of Figure l, parts of the strucure being omitted. p

Figure ,7 is an elevation showing to an enlarged scale t detail of construction, parts being broken away to yize of the figure.Y

stantial variation'.

also substantially continuous, the rotation and heating of the chamber being maintained at approximately a uniform rate throughout the operation of the apparatus. The method of the invention includes continuously merging a supply of gasied carbon tetrachloride with a supply of uranium dioxide, heating the merged materials while agitating them, then discharging separately the produced uranium tetrachloride and the gaseous reaction products, separating unreacted carbon tetrachloride from such reaction products in a continuous fashion, and recycling the separated carbon tetrachloride.

The method of the invention and the mechanism of the invention are both subject to wide practical vaatons. They have both been practiced, however, successfully in apparatus as disclosed herein and by the method disclosed herein.

In the apparatus there is provided a suitable support 6 (Fig. l) which conveniently takes the form of a base 7 supported at an inclination to the horizontal so that the left-hand end, as seen in Figure l, is at a greater height or elevation than the right-hand end, as seen in that gure. Disposed adjacent the lower end of theinclined base 7 is an inclosed heating and vaporizing cham'- ber S, resting upon a suitable heater 9, such as an electric element fastened on a block 11. Electric power is supplied to the heater 9 throughan electric connection 10. Leading into the chamber 8 is a supply conduit 12, ow through which is regulated by a valve 13, manually controllable, and receiving uid from a gauge glass 14. Within the gauge glass a predetermined level 16 of liquid is maintained by suitable operation of a valve 17 interposed in a liquid line 18 connected by a ball joint 19 to the gauge glass 14 and merging with a liquid reservoir 21 substantially closed except for atube 22 which establishes communication between the interior of the reservoir and the atmosphere.

Within the reservoir 21 a supply V01E liquid carbon tetrachloride is maintained and is released by manipulation of the valve 17 for ow into the desired portion of the gauge glass 14. Since release of liquid from the gauge glass 14 is governed by the position of the valve 13, it is possible by properly manipulating the two valves i7 and 13 to maintain the liquid level 16 either constant or within narrow limits, as desired, despite variations of the liquid level in the reservoir 2l.` Sincethe liquid level 16 is substantially constant, there is imposed a pressure or head upon the valve 13 which isapproximately constant, so that a well-regulated, constant flow of liquid Vcarbon tetrachloride through the conduit or pipe 12,4,can

bemaintained despite level variations within the reseryoir 21. ln this fashion,.the supply ofnliquid carbontetrachloride to the chamber S :is c iectuated without sub- The supply of heat through the heating element 9- isr'likewise subject to closeregulation',-s'o

. proach rather that there is evolved within the chamber 8 a carefully regulated, substantially constant supply of gaseous carbon tetrachloride.

The,gaseous carbontetrachloride evolved within the chambenS .is vreleased therefrom through an integral connection 23 to` acontinuously operating reaction mechanism, generally designated 24. This mechanism is supported `on the base '7 partly by a pair of end plates 26 and, 27 which are fastened to the base by suitable securing devices 28 .and 29, so that the end plate 26 is at a greater height or elevation than the end plate 27. The, end plate 27 .(Fig.. 4) is joined through a thermal insulator 31to a reinforcing,disk32united with a-sleeve 33 extending -in coaxial, alignment with a comparable sleeve 34y (Fig. 2) connected to a reinforcing disk 36 joined ,through yan insulating member 37 to the plate 26. ln .approximatecoaxial alignment with the sleeves 33 and 34, and of substantially the same diameter, is an intermediate casing.33, rotatably supported on pairs of rollers 39 and 41, disposed atA opposite sides of and below the axis of rotation of the casing. The roller pairs 39 and 41, respectively, are suitably supported on and fastened to the -base 7 by securing means 42. The casing 38 adjacentone end is provided with a collar 43 (Fig. 4), held in .position by a fastener 44 and contoured to provide a pulley 46 with which is engaged a belt, not shown, driven by.,any suitable source of power, not shown, such as an electric motor. When such motor or other driving mech- .anism is operated, the casing 38 is rotated on the rollers 39 and 41 about its generally inclined longitudinal axis.

4In order that, with the end structures 26 and 27, the casing 38 can provide a substantially closed chamber, -each end ofthe casing 38 is threaded to receive one of a pair of comparably threaded, externally knurled collars 47 and 48, respectively (Figs. l, 2 and 4). Each .of -the collars. 47 and .48 is internally recessed and threaded to receive the associated one of a pair of externally knurled collars 49 and 51. When the collars 49 and 51 ,are relatively rotated with respect to the collars 47 and 48, they are effective to compress packings 52 interposed .between the internally flanged end of the collars 49 and 51 and spacer rings S3 disposed within the interior of the Vrespective collars 47 and 48. For the packing 52, Iohns-Manville` Mogul coil packing, style #223, has been used either as commercially available or having the contained grease partly or completely extracted with carbon tetrachloride. By suitable adjustment of the flanged collars 49 and 51, the packings 52 are compressed to the desired degree upon the sleeves 33` and 34, thereby effectuating a gas-tight, relatively rotatable junction. The

desired position of the flanged collars 49 and 51 is maintained by locking rings S4 and 56, respectively, which ,are externally. knurled, internally threaded members received upon the exterior threads of the anged collars 49 and 51 and jammed against the collars 47 and 48.

Since the chemicals utilized and evolved in the process of the invention are highly corrosive to many materials, and since it is desired to have a satisfactory, long-lived mechanism of relatively inexpensive construction, there is provided within the casing 38 a tubular glass liner 57 (Figs. 2 and 4), disposed coaxially with the casing 38 and held in position by asbestos-graphite packing rings 58, snugly fitting the exterior of the glass liner 57 and .also kclamped between the ends of the casing 38 and a shoulder 59 formed on each of the rings 47 and 48. In order to protect the interior of the structure as much as possible, the liner` 57 is not terminated adjacent the packing rings 58, but rather is axially extended to apclosely the end plates 26 and 27. Since the glass liner 57 does overlie the larger portion of the interior of the structure, such interior is substantially protected from contactwith solid substances contained therein, and particularly the packings 52 are not subjected to .directcontact with such substances and con- .sequentlyV theirglife is lsubstantially increased.

an aperture piercing a Similarly, in order to isolate the more corrosive materials from'the end portions ofthe mechanism, the connector 23 from the chamber 8 which conducts gaseous carbon tetrachloride is led through the end plate 27 to a considerable distance (Fig. 4) into the reaction chamber, generally designated 61, encompassed by the glass liner 57. The connector 23 itself preferably is of glass and is held in its position piercing the end plate 27 by a ring packing 62 clamped in position by a knurled, flanged. nut 63, threaded onto a nipple 64 fastened to the end plate. A spacer .66 serves to compress the packing 62 when the knurled nut 63 is advanced. Gaseous carbon tetrachloride ows through the connector 23, well into the interior of the chamber 61, pastthe packing 52, and is released to the interior of such chamber for reaction therein.

Adjacent the other end of the mechanism, particularly as illustrated lin Figure 1, there is provided a reservoir 67 which contains a renewablesupply of uranimum dioxidein finely-divided, solidform. The reservoir is secured by a Vconnector 68 on the upper threaded end of a nipple 69 extending upwardly from and intersecting a feed tube 71 which is mounted on the end plate 26 and extends well into the interior of the chamber 61, past the packingSZ (seev Fig. 2). In order to feed the solid, finely-divided material from thereservoir to the interior of the chamber, thetube 71 contains and supports a rotatable, helical feed screw 72 which at its outer end issecured to a drive pulley 73, driven by a belt, not shown, from any suitable source of power, not shown, such as an electric motor. Upon appropriate operation of the source of power, preferably by careful regulation thereof, the feed screw 72 is driven at `a rate to supply a constant quantity of finely-divided, solid uranium dioxide to the interior of the chamber 61, conducting the material far enough into the interior of such chamber to reduce substantially the -adverseeffects otherwise imposed upon the packingrSZ. In addition, the length of the tube 71 is such, relative to the momentary volume of uranium dioxide contained, that the material forms a substantially effective seal against the efflux of gas from the chamber 61 to the atmosphere, therebyrnaintaining the air-tight integrity of the structure.

The finely-divided, solid uranium dioxide fed into the upper end of the chamber falls upon the glass liner, and because the liner is rotated and thereby produces agitation, and also because the mechanism is inclined, there is in effect afforded a means for .progressing the introduced solid material `away from the pointof introduction and in a predetermined direction toward a point of discharge. In the meantime, however, the introduced gaseous carbon tetrachloride, because of the incline of the reaction chamber walls and also because of the agitation produced during rotation thereof, traverses the reaction chamber in a turbulent fashion and in a direction opposite to the mentioned predetermined direction.

In order to provide additional agitation, and also tc maintain the interior wall of the glass liner as free as possible from any adheringdeposits, there is dispose within the reaction chamber l61l a combined agitator ant scraper which is constituted by an elongated arcuate chan nel 76 (Figs. 3 and 6) adapted to engage the interior wal of the liner 57 and supported with some freedom ol motion on a plurality of spaced ferrules 77. Each o these is disposed radially of the chamber and is supportet upon an .adjustable pin 78, removably disposed withil longitudinal bar 79 detachabl'4 mounted in the end plates 26 and 27 by fastenings 81 The-positionof the pin 78 is maintained by an adjustable knurled collar `82 threadedly engaging the pin, while th pressure of the channel 76 against the liner is establishe by a coil spring 83 within theV ferrule 77. Since the su; .porting mechanisms are duplicatedat the desired point axially .along .the supporting. bar 79,` a substantially un form pressure of the channel against the liner wall.:

afforded.

ber liner. Due lto the relative rotation between the liner and the channel and its associated mechanism, agitating and scraping effects are produced. By this means the interaction of the solid, inely-divided, continuously introduced uranium dioxide and the gaseous, continuously introduced carbon tetrachloride is promoted.

As an additional means of promoting the chemical reaction, the interior of the reaction chamber 61 is maintained at optimum temperatures over a desired temperature gradient. Preferably, a Vtemperature gradient beginning with approximately 440 C. at the oxide input end and gradually rising to a temperature of approximately 475 C. at the output end is employed. These iigures are not highly critical, although the maintenance of temperatures in this neighborhood is suiicient to enhance the reaction without'unduly increasing the corrosive effects.

To establish the desired'temperature, the reaction chamber, or rather the central portion thereof, is encompassed by heating muffs, -a plurality of which are utilized and but one of which is described, since they are all alike. Each mutt S6 (Fig. ,1) comprisessubstantially identical halves, together encompassing the metallic casing 38 and extending for the desired fraction of the axial length of the reaction chamber, preferably only between those portions intermediate the supporting rollers 3,9 and 41. The lower half 87 of the mulA casing rests uponblocks V88` and` 89 secured to the base 7 by fasteners 91, while the upper casing half 92 is held in assembled position by overlying strips 93 and 94, removably held in position by fastenings 96. A handle 97 is attached to the upper casing half 92 for the operators convenience in removing the top half of the heating muff lfor inspection.

The interior of each muti casing half 87 and 92 is lined with insulating material 98 (Figs. 6 and 7) and is provided with an interior supporting shield 99, against which heating wire 101 is arranged. The wire in the upper muff half is included in an electrical circuit, not shown, by means of a connector 102 mounted on the associated mui half so that when the circuit is closed the wire is heated and Itransmits its heat to the reaction chamber and the contents thereof. A suitable liner 103 assists in maintaining the heating wires in position. Preferably the heating wires in the lower half of the heating muli are in- :luded in a separate circuit by means of va connector 104, 1nd the individual muffs are separately controlledfso that a temperature variation can be etfectuated, preferably the :emperature adjacent the central portion of the reaction :hamber being greater than the ltemperature adjacent the ands thereof.

Because of the rotation of the tube and agitation of :he contents of the reaction chamber and because of the ieat applied thereto, the contained, progressing, solid, inely-divided uranium dioxide and the gaseous counterlowing carbon tetrachloride react to produce, as a solid, :rystalline reaction product, rather finely-divided uraiium tetrachloride which has a high degree of purity. lhe product as formed, being solid and because of the otation of the inclined reaction chamber, continues its tdvance in the predetermined direction to the end of the 'tuer 57, from which it discharges through an outlet tipple 106 (Figs. 1 and 4). This merges with the sleeve `3 and connects through a packing gland 107 to a tube 08 leading into the interior of a receiver 109, resting n a suitable support and adapted to receive the solid eaction product 111. To preclude contamination of uch reaction product, and also to preclude the possibility f escape of any gaseous carbon tetrachloride through 1e receiver 109, an inert atmosphere is supplied to such zceiver. This takes the form, conveniently, of carbon ioxide gas, which is introduced through a conduit 112 l suicient amounts either to maintain the inert atmos- The channel'is-.maintained in substantially fixed position against the relative rotationof the cham-A 6 phere within the receiver 109A or to maintain a slight flow'of gas therethrough into the reaction chamber 61.

The gaseous carbon tetrachloride, which progresses through the reaction chamber in a direction contrary or opposite to the predetermined direction, is .customarily supplied in excess so that while a great part of it reacts within the chamber, there is a part which does not react and which ows, together with other gaseous products of reaction, through the left-hand end of the reaction chamber 61, as seen in Figure 2, into and through a nipple 113 joined ontothe sleeve 34 and affording access through a packing gland 114 (Fig. 1) to an elbow 116 connected to a T 117. The upper branch of the T connects through a packing gland 118 with a conduit 119 extending through a jacket 121. Cooling fluid is released from the jacket through an upper connection 122 and is replenished through a lower supply connection 123. The jacket and the conduit 119 together constitute a condenser, and the temperature maintained within such condenser is eiective to condense the unreacted carbon tetrachloride in the reaction products from its gaseous state back into its liquid state, but is substantially ineifective to condense to the liquid state any of the other gaseous materials present, so that in effect the condenser serves as a separator for removing carbon tetrachloride from the other gaseous reaction products. Uncondensed gases continue their flow 'through the conduit 119 and are discharged at the outlet 124 thereof, while the condensed liquid carbon tetrachloride, being heavy, ows in a reverse direction downward by gravity through the T 117 and through a packing gland 126 on the lower branch of such T, into and through a duct 127 leading to the interior of a receiver 128 suitably supported for containing the condensed, unreacted carbon tetrachloride 129. From time to time, the receiver 128 is detached from the duct 127, and the contents 129 thereof are transferred to the interior of the reservoir 21, so that by this action recovered carbon tetrachloride is re-cycled.

By its operation the described apparatus is effective to carry out the method of the invention and continuously to react finely-divided, solid uranium dioxide with gaseous carbon tetrachloride, to produce reaction gases from which the excess carbon tetrachloride is reclaimed and recycled, and to produce uranium tetrachloride.

What is claimed is:

l. The process for producing uranium tetrachloride comprising continuously introducing finely divided uranium dioxide into an elongated reaction zone having input and discharge points and heated to establish a temperature gradient of from about 440 C. to about 475 C. therebetween, continuously advancing said uranium dioxide through said reaction zone, continuously introducing gaseous carbon tetrachloride at the discharge end of said reaction zone to contact said uranium dioxide in a turbulent countercurrent fashion so as to produce finely divided crystalline uranium tetrachloride therefrom, continuously withdrawing said uranium tetrachloride from the discharge point of said reaction zone, recovering carbon tetrachloride from the efduent gaseous reaction products, and reintroducing the recovered carbon tetrachloride to contact said uranium dioxide.

2. The process for producing uranium tetrachloride comprising continuously advancing iinely divided uranium dioxide through an elongated reaction zone heated to establish a temperature gradient therein from a lower temperature of about 400 C. to a higher temperature of about 475 C. to a discharge point located beyond the higher temperature end thereof, continuously introducing gaseous carbon tetrachloride adjacent to the point of discharge from said reaction zone to contact said uranium dioxide in a turbulent countercurrent fashion so as to produce nely divided crystalline uranium tetrachloride therefrom, and continuously withdrawing said uranium tetrachloride at said discharge point.

3. The method for producing uranium tetrachloride 8 comprising continuously,introducing finely divided uraniat, vwhich said carboiitetrachloride is introduced is also um dioxide intothe, lov/ertemperature end of an elonsubmerged withinthe advancing mass of uranium dioxide, gatedreaction.zoneheated to, establish a temperature vgl-hereby corrosiveiattack of said carbon tetrachloride gradient offrom about 440 C-.to about 475 C, therein, upon the enclosure of said reaction ,zone is minimized. continuously advancing said uranium dioxide through said 5 zone toward a discharge point beyond the higher tem- References Cltedll'l the flleUf hls Patent perature end thereof,v continuously introducing carbon UNITED ySTATES .PATENTS tetrachloride into said reaction 4zone at a location between the ,point at which the uranium dioxide is introduced and 615266 Fogarty Dec' 6 1898 658,727 Naef Sept. 25, 1900 dischargeendrof said reaction zone to contact said uranil0 1,179,394 -Barton Apr. 18, 1916 um dioxide in a turbulent countercurrent fashion to pro- 1,191,804 Lidholm July 18, 1916 duce finely divided crystalline uranium tetrachloride there- 1 230 343 To m I 19 1917 from, and continuously discharging said uranium -tetram asl' une 1,312,743 Moeys Aug. 12, 1919 chloride from said discharge point.

1,358,014 Metzger Nov. 9, 1920 4.,A processfor producing uranium tetrachloride corn- 15 l 646 734 -Ma d O t 25 1927 prising continuouslyintroducing -inely divided uranium 1814392 Lm; etn -1-"'7"'" JCI' 14 1931 dioxidevinto the lower temperature end of an elongated 1904548 S h l a' f Au y 18 1933 reaction zone heatedtto establish a temperature gradient 1918377 11111 Ze 'f Jplr' 18 1933 of from about 440 C; to', 475 C. therein, `continuously 1955272 C c1 ne "l" Au y 17 1934 advancing said uranium dioxide through said Zonetoward 20 2047545 Batfe d a Jplr 14 193 6 adischargetpoint vbeyond the higher temperature end 2070125 Hu -e kz' "i llleyb 9 1937 thereof, continuously, introducing carbon ytetrachloride to 2178685 Ggoc e a "Nv 7 1939 contactsaidl advancing uranium dioxide in a turbulent 2,277,220 Gaey v Mar 24, 1942 countercurrent fashion to.produce finely divided crystalline uranium tetrachloride therefrom, withdrawingthe 25 OTHER REFERENCES uranium .tetrachloride at said discharge point, condensing Menor: Comprehensive Treatise on Theoretieal and Inorganic Chemistry, vol. 12, 1932, page 80.

carbon tetrachloride from eluent reaction gases, and recycling the condensed carbon tetrachloride to contact the Menon Comprehensive Treatise ou Inorganic and advancinguranium-dioxide- Theoreticaichemistr voi x11 i932 a e s3 5.- The process asdenedV in claim 3 wherein said point 30 y p g 

1. THE PROCESS FOR PRODUCING URANIUM TETRACHLORIDE COMPRISING CONTINUOUSLY INTRODUCING FINELY DIVIDED URANIUM DIOXIDE INTO AN ELONGATED REACTION ZONE HAVING INPUT AND DISCHARGE POINTS AND HEATED TO ESTABLISH A TEMPERATURE GRADIENT OF FROM ABOUT 440* C. TO ABOUT 475* C. THEREBETWEEN, CONTINUOUSLY ADVANCING SAID URANIUM DIOXIDE THROUGH SAID REACTION ZONE, CONTINUOUSLY INTRODUCING GASEOUS CARBON TETRACHLORIDE AT THE DISCHARGE END OF SAID REACTION ZONE TO CONTACT SAID URANIUM DIOXIDE IN A TURBULENT COUNTERCURRENT FASHION SO AS TO PRODUCE FINELY DIVIDED CRYSTALLINE URANIUM TETRACHLORIDE THERFROM, CONTINUOUSLY WITHDRAWING SAID URANIUM TETRACHLORIDE FROM THE DISCHARGE POINT OF SAID REACTION ZONE, RECOVERING CARBON TETRACHLORIDE FROM THE EFFLUENT GASEOUS REACTION PRODUCTS, AND REINTRODUCING THE RECOVERED CARBON TETRACHLORIDE TO CONTACT SAID URANIUM DIOXIDE. 